Recurring P3770 Code on 2018 Kenworth T680

I've got a 2018 Kenworth T680 that keeps showing the P3770 code. The check-engine light stays on, and despite multiple visits to the shop for aftertreatment and sensor services, the same code keeps popping up. It’s starting to feel like we’re going in circles here. What could be causing this persistent issue, and what should a qualified technician check first to get to the bottom of it?

Verified source: ODI 11518882 — P3770